The present invention relates to a flexible, flame-retardant, aqueous processable, photoimageable resin composition and a photoimageable element that is flexible after processing and cure. More specifically, the invention relates to a flexible, flame-retardant, aqueous processable, photoimageable resin composition for forming a permanent, protective coating film having excellent properties which can be used for the protection of printed circuitry during its lifetime, and to a multilayer photoimageable element comprising a layer of said composition in combination with a low tack photoimageable resin sublayer and a temporary support film.
The flame-retardant photoimageable resin composition has excellent aqueous developability and yields a cured coating film having good flexibility, ;adhesion, solvent resistance, surface hardness, thermal resistance, electrical insulating properties and Underwriters Laboratory 94VTM-0 flame retardency on flexible polyimide laminates that contain active flame retardants in the adhesive layer, e.g., Pyralux.RTM. FR and Teclam.RTM. (commercially available from E. I. du Pont de Nemours and Company) and on adhesiveless polyimide laminates. The photoimageable resin composition is suitable for use as a solder resist in the fabrication of printed circuit boards.